So far as is known, tubular bags for holding produce for shipment and storage of produce have typically been made of polyethylene. The polyethylene bags are formed from film sheets or bands of relatively impermeable synthetic resin. The polyethylene bags have thus tended to retain moisture in with the produce contents. The retention of moisture in polyethylene bags accelerated the risk of spoilage of the produce in the bags. The polyethylene films could be perforated to allow moisture evaporation and air entry. However, the strength of the polyethylene was materially affected as the number of perforations increased. Further, due to the forming techniques used, polyethylene bags had side edge seams joining two layers of a polyethylene sheet extending upwardly from a lower transverse fold in the sheet. The retention or holding strength of the polyethylene bags was thus also limited by the strength of the side edge seams.
Recently, a woven fabric of cross-laminated synthetic resin fibers known as Cross Laminated Airy Fabric sold under the trademark CLAF.RTM. has been introduced by Amoco Fabrics & Fibers, Inc. This fabric is an open mesh material of cross-laminated warp and weft strands or fibers of synthetic resin. The CLAF.RTM. cross-laminated fiber material has adequate strength for transport and storage of produce. Also, because of the relatively large mesh or spacing of the warp and weft fibers, there was no moisture retention problem as with polyethylene films. However, the CLAF.RTM. cross-laminated fiber material was not suitable for forming into bags with techniques like those used with polyethylene films. The spaced strands at edges of the materials could not be heat sealed together with adequate holding strength for produce bag purposes.